Nonwoven materials made by many different processes have been utilized as components to produce absorbent materials for use in feminine hygiene, infant diapers and incontinence products. Modern technologies utilizing fluff pulp structures, often combined with other non-woven materials to form multilayer composite, have been used to facilitate fluid capture, distribution and containment. Other materials such as superabsorbent polymers are often incorporated in these composites to maximize fluid containment.
WO 99/27876, WO 99/27879, WO 99/30661, WO 00/56258 and WO 01/72253 A1, (SCA Hygiene Products AB) and US 2002/0026699A1, US 2002/0029026A1, US 2002/0028624A1, US 2002/0029023A1, US 2002/0029024A1, US 2002/0029025A1 and US 2002/0049419A1 (Uni-Charm Corporation) all describe use of filament “tows” as a fluid acquisition material in infant diapers and the like but as only one component in the absorbent matrices specified. More particularly, these specifications disclose production of a layer or layers of continuous “tow” filaments which are bonded in various ways and which may be of cellulose acetate, or of polyethylene, polypropylene, polyamide, polyester, polyvinyl acetate, viscose or rayon, or bi-component polymers. Steps in production of said layer can include crimping or curling, then stretching and distributing the “tow” filaments in various ways, then bonding same in a pattern of lines, spots or points by any suitable technique including thermal or ultrasonic bonding, calendering, laser or print-bonding or undefined hydroentanglement. The filaments are cut to length either before or after the aforesaid bonding. Optionally in some cases, the “tow” filaments can be bonded, at the same time as the pattern of bonding mentioned above, to a liquid containment layer which can be a non-woven composite material. In some cases, some further details are provided of the method of handling the “tow” filaments to produce a finished layer or layers. The prior art describes conventional bonding of tow filaments by various techniques, all of which depress the performance of such tow assemblies by capillary blockage at points of bonding.